The BMW 4 Series Coupe (F32), specifically the 420d variant with the Steptronic automatic transmission, was produced from 2017 to 2020 as part of the F32’s lifecycle facelift. This model occupied a key position in the 4 Series lineup, offering a balance between performance, efficiency, and affordability. It aimed to provide a more accessible entry point into the 4 Series range while still delivering the core BMW driving experience. The 420d Steptronic was positioned below the more powerful 430d and 440i models, targeting buyers who prioritized fuel economy and comfortable cruising over outright speed.
Technical Specifications
| Brand | BMW |
| Model | 4 Series |
| Generation | 4 Series Coupe (F32, facelift 2017) |
| Type (Engine) | 420d (190 Hp) Steptronic |
| Start of production | 2017 |
| End of production | 2020 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 4.7-5.1 l/100 km (50 – 46.1 US mpg, 60.1 – 55.4 UK mpg, 21.3 – 19.6 km/l) |
| Fuel consumption (extra urban) | 3.6-3.9 l/100 km (65.3 – 60.3 US mpg, 78.5 – 72.4 UK mpg, 27.8 – 25.6 km/l) |
| Fuel consumption (combined) | 4.0-4.3 l/100 km (58.8 – 54.7 US mpg, 70.6 – 65.7 UK mpg, 25 – 23.3 km/l) |
| CO2 emissions | 106-114 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 7.1 sec |
| Acceleration 0 – 62 mph | 7.1 sec |
| Acceleration 0 – 60 mph | 6.7 sec |
| Maximum speed | 232 km/h (144.16 mph) |
| Emission standard | Euro 6 |
| Weight-to-power ratio | 7.9 kg/Hp, 126.7 Hp/tonne |
| Weight-to-torque ratio | 3.8 kg/Nm, 266.7 Nm/tonne |
| Power | 190 Hp @ 4000 rpm |
| Torque | 400 Nm @ 1750-2500 rpm (295.02 lb.-ft. @ 1750-2500 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | B47D20A |
| Engine displacement | 1995 cm3 (121.74 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 90 mm (3.54 in.) |
| Compression ratio | 16.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Twin-power turbo, Intercooler |
| Engine oil capacity | 5 l (5.28 US qt | 4.4 UK qt) |
| Coolant | 7 l (7.4 US qt | 6.16 UK qt) |
| Kerb Weight | 1500 kg (3306.93 lbs.) |
| Max. weight | 2020 kg (4453.34 lbs.) |
| Max load | 520 kg (1146.4 lbs.) |
| Trunk (boot) space – minimum | 445 l (15.72 cu. ft.) |
| Fuel tank capacity | 57 l (15.06 US gal | 12.54 UK gal) |
| Max. roof load | 75 kg (165.35 lbs.) |
| Permitted trailer load with brakes (12%) | 1600 kg (3527.4 lbs.) |
| Permitted trailer load without brakes | 745 kg (1642.44 lbs.) |
| Permitted towbar download | 75 kg (165.35 lbs.) |
| Length | 4640 mm (182.68 in.) |
| Width | 1825 mm (71.85 in.) |
| Height | 1377 mm (54.21 in.) |
| Wheelbase | 2810 mm (110.63 in.) |
| Front track | 1547 mm (60.91 in.) |
| Rear (Back) track | 1593 mm (62.72 in.) |
| Ride height (ground clearance) | 130 mm (5.12 in.) |
| Drag coefficient (Cd) | 0.28 |
| Minimum turning circle (turning diameter) | 11.3 m (37.07 ft.) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 8 gears, automatic transmission Steptronic |
| Front suspension | Independent coil spring |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Tires size | 225/50 R17; 225/45 R18; 255/40 R18; 225/40 R19; 255/35 R19 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 18; 8J x 19; 8.5J x 19 |
Powertrain & Engine Architecture
The heart of the 420d Steptronic is the BMW B47D20A 2.0-liter inline-four diesel engine. This engine is a member of BMW’s modular engine family, known for its efficiency and refinement. It utilizes a second-generation common rail direct injection system operating at pressures up to 2,000 bar, ensuring precise fuel delivery and optimized combustion. The B47 features a single twin-scroll turbocharger with variable geometry turbine (VGT) technology, along with an intercooler, to minimize turbo lag and maximize power output across the rev range. The engine also incorporates BMW’s BluePower technology, including a diesel particulate filter (DPF) and NOx catalyst, to meet stringent Euro 6 emission standards. The Steptronic transmission is an 8-speed automatic gearbox, offering smooth and quick shifts. It features adaptive shift programs that adjust to the driver’s style and road conditions.
Driving Characteristics
The 420d Steptronic delivers a comfortable and refined driving experience. While not as overtly sporty as the higher-powered 4 Series variants, it provides ample torque for everyday driving and confident overtaking. The 400 Nm of torque, available from 1750-2500 rpm, provides strong acceleration in most situations. The Steptronic transmission contributes to a relaxed driving experience, particularly in urban environments. Compared to the 6-speed manual version, the Steptronic offers smoother gear changes and reduces driver fatigue. However, some enthusiasts might find the automatic transmission less engaging than the manual option. The 0-60 mph time of around 6.7 seconds is respectable, but noticeably slower than the 430d or 440i models. The rear-wheel-drive configuration provides balanced handling, although traction can be limited in wet or slippery conditions.
Equipment & Trim Levels
The 420d Steptronic typically came equipped with a generous amount of standard features. These included BMW’s iDrive infotainment system with a 6.5-inch display (later upgraded to 8.8 inches), automatic climate control, rain-sensing wipers, and a leather-wrapped steering wheel. Upholstery was typically cloth or a combination of cloth and leatherette. Optional extras included leather seats, a sunroof, a premium sound system, navigation, and various driver-assistance systems such as lane departure warning and adaptive cruise control. The Sport Line trim package added more aggressive styling cues, sport seats, and a sport suspension. The Luxury Line offered a more elegant appearance with chrome accents and wood trim.
Chassis & Braking
The 420d Steptronic utilizes a sophisticated chassis design. The front suspension features independent coil springs and struts, while the rear suspension employs an independent multi-link setup. This configuration provides a good balance between ride comfort and handling precision. The steering is a rack-and-pinion system with electric power assistance. Braking duties are handled by ventilated disc brakes on all four wheels, providing ample stopping power. ABS (Anti-lock Braking System) is standard, along with electronic stability control and traction control. The 420d’s weight of around 1500 kg is relatively well-distributed, contributing to balanced handling characteristics.
Market Reception & Comparison
The 420d Steptronic was generally well-received by automotive critics. It was praised for its fuel efficiency, comfortable ride, and refined engine. However, some reviewers noted that it lacked the outright performance of its more powerful siblings. Compared to the 430d, the 420d offered significantly lower running costs but sacrificed some performance. The 420d was also a more affordable alternative to the 440i, which offered a more potent gasoline engine. In terms of reliability, the B47 engine has proven to be generally robust, although some early models experienced issues with the timing chain.
Legacy
The BMW 420d Steptronic remains a popular choice in the used car market. Its combination of fuel efficiency, comfort, and BMW build quality makes it an attractive option for buyers seeking a stylish and practical coupe. The B47 engine, while not without its potential issues, has proven to be relatively durable when properly maintained. Regular servicing, including oil changes and timing chain inspections, is crucial to ensure long-term reliability. The 420d Steptronic represents a well-rounded package within the F32 4 Series lineup, offering a compelling blend of performance, efficiency, and luxury.
